The helicopter also comprises at least one engine; a transmission between the engine and the drive shaft; and a connecting device connecting the fuselage to a supporting body supporting the drive shaft and the transmission. In other words, the fuselage is “suspended” from the supporting body by the connecting device.
During normal operation of the helicopter, the engine exerts drive torque on the transmission. By the law of action-reaction, reaction torque is transmitted to the supporting body, and from there to the fuselage by the connecting device, and is balanced by an opposing torque exerted on the fuselage by the tail rotor.
The connecting device inevitably transmits vibration and noise to the fuselage and hence to the cabin, thus impairing the comfort of the crew.
A need is felt within the industry to minimize transmission of this vibration and noise to the cabin, particularly in predetermined frequency ranges.